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Alegrete, Brazil

Dias-Da-Silva S.,Federal University of Pampa | Marsicano C.,Laboratorio Of Paleontologia Of Vertebrados
Journal of Systematic Palaeontology | Year: 2011

All stereospondyl taxa previously placed within Rhytidosteidae are reviewed in a phylogenetic context. A parsimony analysis shows that Pneumatostega, Trucheosaurus, Rhytidosteus and Nanolania are placed outside Rhytidosteidae. If an implied weighting method is introduced in order to downweight homoplastic characters, then these taxa are placed within rhytidosteids (with the exception of Rhytidosteus), thus forming a resolved monophyletic group. This group is supported by four synapomorphies, including a twisted pterygoid quadrate ramus and sculpture consisting of a reticulate pattern with pustules or nodules at the junction between adjacent crests and ridges. Based on the topology of a majority rule consensus tree, we postulate a close relationship among all eastern Gondwanan rhytidosteids (Australian and Indian taxa) and among western Gondwanan taxa (South America, South Africa and Madagascar). Laurasian Boreopelta and Peltostega are successive paraphyletic taxa of both eastern and western groups. The Australian family 'Derwentiidae' is nested within Rhytidosteidae and is redefined as a subfamily (Derwentiinae nov.) which also includes Indobrachyops. Peltosteginae and Indobrachyopidae as currently defined in the literature are not supported. Rhytidosteinae is also not supported because Laidleria, Pneumatostega and Rhytidosteus do not emerge as a clade. The presence of the rhytidosteid Trucheosaurus major in the Late Permian of Australia suggests that rhytidosteids were already diversified at that time. Increasing efforts to collect Upper Permian and Lower Triassic rhytidosteids should help to improve stratigraphical, palaeogeographical and phylogenetic information regarding this widespread group of temnospondyls. Copyright © 2011 The Natural History Museum. Source

Farina M.,Federal University of Santa Catarina | Avila D.S.,Federal University of Pampa | Da Rocha J.B.T.,Federal University of Santa Maria | Aschner M.,Vanderbilt University
Neurochemistry International | Year: 2013

Essential metals are crucial for the maintenance of cell homeostasis. Among the 23 elements that have known physiological functions in humans, 12 are metals, including iron (Fe) and manganese (Mn). Nevertheless, excessive exposure to these metals may lead to pathological conditions, including neurodegeneration. Similarly, exposure to metals that do not have known biological functions, such as mercury (Hg), also present great health concerns. This review focuses on the neurodegenerative mechanisms and effects of Fe, Mn and Hg. Oxidative stress (OS), particularly in mitochondria, is a common feature of Fe, Mn and Hg toxicity. However, the primary molecular targets triggering OS are distinct. Free cationic iron is a potent pro-oxidant and can initiate a set of reactions that form extremely reactive products, such as Oh. Mn can oxidize dopamine (DA), generating reactive species and also affect mitochondrial function, leading to accumulation of metabolites and culminating with OS. Cationic Hg forms have strong affinity for nucleophiles, such as -SH and -SeH. Therefore, they target critical thiol- and selenol-molecules with antioxidant properties. Finally, we address the main sources of exposure to these metals, their transport mechanisms into the brain, and therapeutic modalities to mitigate their neurotoxic effects. © 2012 Elsevier Ltd. All rights reserved. Source

Grigoletto F.B.,Federal University of Pampa | Pinheiro H.,Federal University of Santa Maria
IEEE Transactions on Industrial Electronics | Year: 2014

This paper presents a new flexible arrangement of static converters for grid-connected wind energy conversion systems (WECS). The proposed arrangement uses three-phase voltage-fed back-to-back mass-produced power converter modules with reconfiguration switches. The main features of the proposed flexible arrangement are as follows: 1) expanded reactive power capability limits; 2) high efficiency, mainly under low wind conditions where the active power is reduced; and 3) low current harmonic content. In addition, a detailed description of the operating modes, as well as of the grid, generator, and circulating current controller design, are given. Finally, experimental results support the theoretical development, and demonstrate the good performance and flexibility of the proposed arrangement. © 1982-2012 IEEE. Source

Various health complications have been identified among teachers and there is little information available about their lifestyle habits. The scope of this study was to investigate health conditions, lifestyles and occupational characteristics of municipal teachers in Bagé in the south of Brazil. A cross-sectional study involving 414 teachers was conducted by asking the teachers to fill out a standardized questionnaire. Descriptive and bivariate analysis techniques were employed. Most teachers were females (96.1%) and the mean age was 40.1 years (SD 9.4). Average teaching experience was 12.4 years (SD 9.5); 59% of the teachers had a degree; they taught many working hours per week (31.7 hours, SD 10.5) and 62% were absent from work at least once in the last 12 months. Self-rated heath was good (38.5%); 62.5% of them were physically active; 32.3% were overweight and 14.4% obese. They consumed hardly any fruit and vegetables (79.6%), had average stress levels of 14.9 points (SD 6.6) and 20.3% reported hypertension. Self-reported health was associated with teaching time, absenteeism, physical activity, number of meals per day, stress levels and hypertension. The prevalence of teachers who rated their health negatively was low, however several lifestyle issues were identified, which can be prejudicial to the health of these individuals. Source

de David A.C.,University of Brasilia | Carpes F.P.,Federal University of Pampa | Stefanyshyn D.,University of Calgary
Journal of Sports Sciences | Year: 2015

Joint moments can be used as an indicator of joint loading and have potential application for sports performance and injury prevention. The effects of changing walking and running speeds on joint moments for the different planes of motion still are debatable. Here, we compared knee and ankle moments during walking and running at different speeds. Data were collected from 11 recreational male runners to determine knee and ankle joint moments during different conditions. Conditions include walking at a comfortable speed (self-selected pacing), fast walking (fastest speed possible), slow running (speed corresponding to 30% slower than running) and running (at 4 m · s−1 ± 10%). A different joint moment pattern was observed between walking and running. We observed a general increase in joint load for sagittal and frontal planes as speed increased, while the effects of speed were not clear in the transverse plane moments. Although differences tend to be more pronounced when gait changed from walking to running, the peak moments, in general, increased when speed increased from comfortable walking to fast walking and from slow running to running mainly in the sagittal and frontal planes. Knee flexion moment was higher in walking than in running due to larger knee extension. Results suggest caution when recommending walking over running in an attempt to reduce knee joint loading. The different effects of speed increments during walking and running should be considered with regard to the prevention of injuries and for rehabilitation purposes. © 2014, © 2014 Taylor & Francis. Source

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